Method of forming flat strip stepped slab floor system of reinforced concrete

ABSTRACT

A system and a method for a reinforced concrete slab are disclosed. The system includes a plurality of column strips of a predefined thickness positioned on a plurality of columns, a plurality of transitional strips positioned adjacent to the plurality of column strips, whereby a thickness of the plurality of transitional strips comparatively less than the predefined thickness of the plurality of column strips, a central panel bound by the plurality of transitional strips, whereby the thickness of the central panel comparatively less than the thickness of the plurality of transitional strips and a plurality of column steps positioned in between the plurality of columns and the plurality of column strips.

TECHNICAL FIELD OF THE INVENTION

The present invention generally relates to a field of reinforcedconcrete slab construction. More particularly the present invention isrelated to a flat strip slab system.

BACKGROUND OF THE INVENTION

Beam-slab construction is the most popular floor system in reinforcedconcrete construction. The conventional systems suffer from drawbacks ofincreased shuttering and insitu works, extensive rebar fabrication,congestion of column beam junctions which are structurally critical.Failures during earthquakes amply demonstrate the weakness of beam slabfloor system present in the conventional system.

Typically, flat slabs or flat plates are a common alternatives to thebeam slab floor system. Due to uniform thickness, flat slabs demandhigher slab thickness resulting into higher dead weight and higherconsumption of material thereby increasing the cost of a construction.

Generally, flat plate slabs illustrated in FIG. 1 rests directly on topof the columns which support them, wherein the flat plate slabs aresubjected to large bending moments, shearing forces and the effect ofthese high shears and flexural stress can cause failure by “punching” ofthe slab at the column-slab junction. Inappropriate distribution of thematerial in the flat plate slab system offers less resistance againstlateral loading. Further flexural Stress distribution in flat slabsindicates highly under utilization and concentration of moment peaks ata limited zone around columns. Such peak concentration at a fewlocations making the flat plate slab susceptible for early failures.

Based on forgone experiences with the above systems, in order toovercome some design deficiencies, wide beam-slab system illustrated inFIG. 2 is developed. Wide beam and flat slab systems define column stripand rest of the slab area as depicted in FIG. 3. The series 1 representsflat slab system and series 2 represents wide beam system in FIG. 3. Theimproved wide beam and flat slab systems does not ensure smooth transferof stresses and having a lower utility ratio as shown in FIG. 3.

A column supported concrete slab disclosed in U.S. Pat. No. 4,406,103described controlling the diagonal shear cracks in the vicinity of thecolumn zone by providing specific inserts in the both intent and contentof the patent under reference is differ from the present invention interms of transitional strips to enable normalizing the stress peaksbetween column strips and middle strips accordingly the presentinvention leads to stepped slab, whereas stepped slab of linear stripsforming closed boundaries. The embodiments described in U.S. Pat. No.4,406,103 in concrete deals with a conventional flat slab which includesuniform thickness. Flat slab requires higher slab thickness resultinginto higher dead weight and higher consumption of material therebyincreasing the cost of a construction.

Hence there exists a need for a system and a method to achieve anoptimized slab system for an optimal distribution of stresses, possibleimprovement under lateral loading and efficient utilization of materialin a reinforced concrete slab.

BRIEF SUMMARY OF THE INVENTION

A system and a method for a reinforced concrete slab are disclosed.According to a first aspect of the present invention, a system for areinforced concrete slab includes a plurality of column strips of apredefined thickness positioned on a plurality of columns.

According to the first aspect of the present invention, the system for areinforced concrete slab includes a plurality of transitional stripspositioned adjacent to the plurality of column strips, whereby athickness of the plurality of transitional strips comparatively lessthan the predefined thickness of the plurality of column strips.

According to the first aspect of the present invention, the system for areinforced concrete slab includes a central panel bound by the pluralityof transitional strips, whereby the thickness of the central panelcomparatively less than the thickness of the plurality of transitionalstrips.

According to a second aspect of a present invention, a system for areinforced concrete slab is disclosed. According to the second aspect ofthe present invention, the system for a reinforced concrete slabincludes a plurality of column steps positioned in between the pluralityof columns and the plurality of column strips.

According to a third aspect of a present invention, a method for areinforced concrete slab is disclosed. According to the third aspect ofthe present invention, the method for a reinforced concrete slabincludes positioning a plurality of column strips of predefinedthickness on a plurality of columns.

According to the third aspect of the present invention, the method for areinforced concrete slab includes positioning a plurality oftransitional strips adjacent to the plurality of column strips, wherebya thickness of the plurality of transitional strips comparatively lessthan the predefined thickness of the plurality of column strips. A stepof varying the thickness of the strips at a predefined regular intervalenables the optimal distribution of stresses in the reinforced concreteslab.

According to the third aspect of the present invention, the method for areinforced concrete slab includes bounding a central panel by theplurality of transitional strips, whereby the thickness of the centralpanel comparatively less than the thickness of the plurality oftransitional strips.

According to a fourth aspect of a present invention, a method for areinforced concrete slab is disclosed. According to the fourth aspect ofthe present invention, the method for a reinforced concrete slabincludes positioning a plurality of column steps in between theplurality of columns and the plurality of column strips.

BRIEF DESCRIPTION OF THE DRAWINGS

Other objects and advantages of the present invention will becomeapparent to those skilled in the art upon reading the following detaileddescription of the preferred embodiments, in conjunction with theaccompanying drawings, wherein like reference numerals have been used todesignate like elements, and wherein:

FIG. 1 is a diagram depicting a typical part plan of a conventional flatslab system.

FIG. 2 is a diagram depicting a typical part plan of a conventional widebeam slab system.

FIG. 3 is a diagram depicting a graphical representation of utilityratio in conventional slab systems.

FIG. 4 is a diagram depicting a typical part plan of a flat strip slabsystem.

FIG. 5 is a diagram depicting a typical part plan of a flat strip slabsystem with multiple column steps.

FIG. 6 is a diagram depicting a cross sectional view of a flat stripslab system through a central panel.

FIG. 7 a is a diagram depicting a cross sectional view of a flat stripslab system with multiple column steps.

FIG. 7 b is a diagram depicting a cross sectional view of a column steps

FIG. 8 is a diagram depicting an overview of a flat strip slab system.

FIG. 9 is a diagram depicting a graphical representation of utilityratio in different slab systems.

DETAILED DESCRIPTION OF THE INVENTION

It is to be understood that the present disclosure is not limited in itsapplication to the details of construction and the arrangement ofcomponents set forth in the following description or illustrated in thedrawings. The present disclosure is capable of other embodiments and ofbeing practiced or of being carried out in various ways. Also, it is tobe understood that the phraseology and terminology used herein is forthe purpose of description and should not be regarded as limiting.

The use of “including”, “comprising” or “having” and variations thereofherein is meant to encompass the items listed thereafter and equivalentsthereof as well as additional items. The terms “a” and “an” herein donot denote a limitation of quantity, but rather denote the presence ofat least one of the referenced item. Further, the use of terms “first”,“second”, and “third”, and the like, herein do not denote any order,quantity, or importance, but rather are used to distinguish one elementfrom another.

Exemplary embodiments of the present invention are directed towards asystem and a method for a reinforced concrete slab. According to a firstaspect of a present invention, a system for the reinforced concrete slabincludes a plurality of column strips of a predefined thicknesspositioned on a plurality of columns.

According to the first aspect of the present invention, the system for areinforced concrete slab includes a plurality of transitional stripspositioned adjacent to the plurality of column strips, whereby athickness of the plurality of transitional strips comparatively lessthan the predefined thickness of the plurality of column strips.

According to the first aspect of the present invention, the system for areinforced concrete slab includes a central panel bound by the pluralityof transitional strips, whereby the thickness of the central panelcomparatively less than the thickness of the plurality of transitionalstrips.

According to a second aspect of a present invention, a system for areinforced concrete slab is disclosed. According to the second aspect ofthe present invention, the system for a reinforced concrete slabincludes a plurality of column steps positioned in between the pluralityof columns and the plurality of column strips.

According to a third aspect of a present invention, a method for areinforced concrete slab is disclosed. According to the third aspect ofthe present invention, the method for a reinforced concrete slabincludes positioning a plurality of column strips of predefinedthickness on a plurality of columns.

According to the third aspect of the present invention, the method for areinforced concrete slab includes positioning a plurality oftransitional strips adjacent to the plurality of column strips, wherebya thickness of the plurality of transitional strips comparatively lessthan the predefined thickness of the plurality of column strips. A stepof varying the thickness of the strips at a predefined regular intervalenables the optimal distribution of stresses in the reinforced concreteslab.

According to the third aspect of the present invention, the method for areinforced concrete slab includes bounding a central panel by theplurality of transitional strips, whereby the thickness of the centralpanel comparatively less than the thickness of the plurality oftransitional strips.

According to a fourth aspect of a present invention, a method for areinforced concrete slab is disclosed. According to the fourth aspect ofthe present invention, the method for a reinforced concrete slabincludes positioning a plurality of column steps in between theplurality of columns and the plurality of column strips.

Referring to FIG. 4 is a diagram 400 depicting a typical part plan of aflat strip slab system. In accordance with a non limiting exemplaryembodiment of the present invention, a system for a reinforced concreteslab includes multiple columns 402 a, 402 b, 402 c and 402 d, multiplecolumn strips 404 a, 404 b, 404 c and 404 d, multiple transitionalstrips 406 a, 406 b, 406 c and 406 d and a central panel 408 bound bymultiple transitional strips 406 a, 406 b, 406 c, 406 d.

In accordance with an exemplary embodiment of the present invention, thecolumn strips 404 a, 404 b, 404 c and 404 d of a predefined thicknessare positioned on the columns 402 a, 402 b, 402 c and 402 d. Thetransitional strips 406 a, 406 b, 406 c and 406 d are positionedadjacent to the column strips 404 a, 404 b, 404 c and 404 d. Thethickness of the transitional strips 406 a, 406 b, 406 c and 406 d iscomparatively less than the predefined thickness of the column strips404 a, 404 b, 404 c and 404 d. The central panel 408 is bounded by thetransitional strips 406 a, 406 b, 406 c and 406 d. The thickness of thecentral panel 408 is comparatively less than the thickness of thetransitional strips 406 a, 406 b, 406 c and 406 d.

According to a non limiting exemplary embodiment of the presentinvention, the thickness of the slab is varied from the column strips404 a, 404 b, 404 c and 404 d to the central panel 408 for enabling theoptimal distribution of stresses in the reinforced concrete slab andalso for an efficient utilization of the structural sections provided onthe reinforced concrete slab.

Referring to FIG. 5 is a diagram 500 depicting a typical part plan of aflat strip slab system with multiple column steps. In accordance with anon limiting exemplary embodiment of the present invention, a system fora reinforced concrete slab includes multiple columns 502 a, 502 b, 502 cand 502 d, multiple column steps 504 a, 504 b, 504 c and 504 d, multiplecolumn strips 506 a, 506 b, 506 c and 506 d, multiple transitionalstrips 508 a, 508 b, 508 c and 508 d and a central panel 520 bound bythe multiple transitional strips 508 a, 508 b, 508 c and 508 d.

Referring FIG. 6 is a diagram 600 depicting a cross sectional view of aflat strip slab system through central panel. In accordance with a nonlimiting exemplary embodiment of the present invention, the crosssectional view of the flat strip slab system depicts multiple columns602 a and 602 b, multiple column strips 604 a and 604 b, multipletransitional strips 606 a and 606 b and a central panel 608.

In accordance with an exemplary embodiment of the present invention, thecolumn strips 604 a and 604 b of a predefined thickness are positionedon the columns 602 a and 602 b. The transitional strips 606 a and 606 bare positioned adjacent to the column strips 604 a and 604 b. Thethickness of the transitional strips 606 a and 606 b is comparativelyless than the predefined thickness of the column strips 604 a and 604 b.The central panel 608 is bound by the transitional strips 606 a and 606b. The thickness of the central panel 608 is comparatively less than thethickness of the transitional strips 606 a and 606 b.

Referring to FIG. 7 a is a diagram 700 a depicting a cross sectionalview of a flat strip slab system with multiple column steps through acolumn strip. In accordance with a non limiting exemplary embodiment ofthe present invention, the cross sectional view of a flat strip slabwith multiple column steps depicts multiple columns 702 a and 702 b,multiple column steps 704 a, 704 b and a column strip 706.

In accordance with an exemplary embodiment of the present invention, thecolumns strip 706 of a predefined thickness is positioned on columns 702a and 702 b. The multiple column steps 704 a and 704 b are positioned inbetween the columns 702 a and 702 b and the column strip 706 to achievean optimal distribution of stresses in the reinforced concrete flatstrip slab.

Referring to FIG. 7 b is a diagram 700 b depicting a cross sectionalview of a column steps. In accordance with a non limiting exemplaryembodiment of the present invention, the cross sectional view of acolumn steps depicts a column 702, a column steps 704, and a slab castportion 708.

In accordance with an exemplary embodiment of the present invention, thecolumn steps 704 is positioned in between the column 702 and the slabcast portion 708 to achieve the optimal distribution of stresses in thereinforced concrete flat strip slab. The slab cast portion 708 ispositioned over column steps 704.

Referring FIG. 8 is a diagram 800 depicting an overview of a flat stripslab system. In accordance with a non limiting exemplary embodiment ofthe present invention, the overview of a flat strip slab system depictsa column strip 802, a transitional strip 804 and a central panel 806.

In accordance with an exemplary embodiment of the present invention, thecolumn strip 802 of a predefined thickness is positioned on the columns.The transitional strip 804 is positioned adjacent to the column strip802. The thickness of the transitional strip 804 is comparatively lessthan the predefined thickness of the column strip 802. The central panel806 is bound by the transitional strips 804. The thickness of thecentral panel 806 is comparatively less than the thickness of thetransitional strip.

According to a non limiting exemplary embodiment of the presentinvention, the thickness of the slab is varied from the column strips802 to the central panel 806 for enabling the optimal distribution ofstresses in the reinforced concrete slab and for an efficientutilization of the structural sections provided.

Referring FIG. 9 is a diagram 900 depicting a graphical representationof utility ratio in different slab systems. In accordance with a nonlimiting exemplary embodiment of the present invention, the graphicalrepresentation of ratio in different slab systems is depicted in series1, series 2 and series 3.

In accordance with an exemplary embodiment of the present invention,utility ratio is taken as a ratio of applied average moment to moment ofresistance of section under reference using consistence units as shownin a flat strip slab system as ability to achieve higher utility ratioagainst to flat slab system and wide beam system.

In accordance with an exemplary embodiment of the present invention,series 1 represents a flat strip slab system, series 2 represents a flatslab system and series 3 represents a wide beam system. Span locationtaken along x-axis and the utility ratio is taken along Y-axis and agraph is plotted for the flat strip slab system, the flat slab systemand wide beam system. The graph shows higher utility ratio in the flatstrip slab system when compared with the flat slab system and the widebeam system. The plot between the span location 1 and the span location3 represents the utility ratio of a column strip, the plot between thespan location 3 and the span location 4 represents the utility ratio ofa transitional strip, the plot between the span location 4 and the spanlocation 10 represents the utility ratio of a middle strip, the plotbetween the span location 10 and the span location 11 represents theutility ratio of the transitional strip and the plot between the spanlocation 11 and the span location 13 represents the utility ratio of thecolumn strip in the flat strip slab system, the flat slab system and thewide beam system.

According to a non limiting exemplary embodiment of the presentinvention, the purpose of transitional strip in the flat strip slabsystem is to smoothen out stress peaks between column strip and middlestrip. This feature make rove appropriate to improve lateral forceresisting ability of slabs particularly an encountered with rigid shearwalls where stress peaks are very high.

As will be appreciated by a person skilled in the art the presentinvention provides a variety of advantages. Firstly, the invention isdesigned for all possible load cases of both gravity and lateral loads.Secondly, the invention provides an efficient stress leveling withoptimal distribution of stresses. Thirdly, the flat strip slabs consumesless amount of concrete compared to the other conventional systems.Fourthly, the invention provides an economical and elegant alternativeto the conventional floor systems.

While specific embodiments of the invention have been shown anddescribed in detail to illustrate the inventive principles, it will beunderstood that the invention may be embodied otherwise withoutdeparting from such principles.

1. A reinforced concrete slab system, comprising: a plurality of column strips of a predefined thickness positioned on a plurality of columns; a plurality of transitional strips positioned adjacent to the plurality of column strips, whereby a thickness of the plurality of transitional strips comparatively less than the predefined thickness of the plurality of column strips; and a central panel bound by the plurality of transitional strips, whereby the thickness of the central panel comparatively less than the thickness of the plurality of transitional strips.
 2. A system for a reinforced concrete slab, comprising: a plurality of column strips of a predefined thickness positioned on a plurality of columns; a plurality of transitional strips positioned adjacent to the plurality of column strips, whereby a thickness of the plurality of transitional strips comparatively less than the predefined thickness of the plurality of column strips; a central panel bound by the plurality of transitional strips, whereby the thickness of the central panel comparatively less than the thickness of the plurality of transitional strips; and a plurality of column steps positioned in between the plurality of columns and the plurality of column strips;
 3. A method for a reinforced concrete slab, comprising: positioning a plurality of column strips of predefined thickness on a plurality of columns; positioning a plurality of transitional strips adjacent to the plurality of column strips, whereby a thickness of the plurality of transitional strips comparatively less than the predefined thickness of the plurality of column strips; and bounding a central panel by the plurality of transitional strips, whereby the thickness of the central panel comparatively less than the thickness of the plurality of transitional strips.
 4. The method of claim 4, wherein a step of varying the thickness of the strips at a predefined regular interval enables the optimal distribution of stresses in the reinforced concrete slab.
 5. A method for a reinforced concrete slab, comprising: positioning a plurality of column strips of predefined thickness on a plurality of columns; positioning a plurality of transitional strips adjacent to the plurality of column strips, whereby a thickness of the plurality of transitional strips comparatively less than the predefined thickness of the plurality of column strips; bounding a central panel by the plurality of transitional strips, whereby the thickness of the central panel comparatively less than the thickness of the plurality of transitional strips; and positioning a plurality of column steps in between the plurality of columns and the plurality of column strips. 